How to test amp hour

[FlyingBeagle]

i agree with ESPEE fan for the most part. I have a good bit of experience with LIPO packs as most of my hobby time has been spent with Air Planes. I have several planes that run on LIPO packs and probably 25 packs of various size and voltages. LIPO's are finicky, and there are a lot of rules of thumb that you will hear from people some true, and some B.S. LIPO packs also vary widely in the quality between manufactureres and a lot of manufactures claims for capacity and C ratings are optimistic at best. As you would expect you usually get what you pay for although I have some cheap rhino packs from Hobby King that have out lasted and performed all the others in my collection.

I never discharge my packs below 3.3V per cell. Most flights I only take them down to about 3.6V per cell. My packs have all given me a good life cycle and I have only had one go bad so far and it was a cheap pack that never performed well in the first place.

I never cycle my packs unless I am trying to get one to balance as they do not have memory problems like other types of packs and they only have a certain number of cycles before they go bad. Why accelerate thier demise? Also if it is very far out of balance there is usually a bigger problem with the pack and I would be suspicious of it and probably just get rid of it. I may cycle it once to see if it is fixed, but if not it would be gone.

I always, balance charge them. I never charge them at more than 2C rate (4.4 amps for a 2200mah pack).

If they are going to be sitting for a while I store them at 3.6V~3.8V per cell. I never store them for more than a week fully charged.

Lipos do not like to be abused, and can become dangerous if they are not properly cared for. I had a pack with a bad cell go off in my hands as I was about to dispose of it because it would not balance. I was getting it out of the case and was going to puncture it in a fire pit with a spike when it just went off in my hands. 1 Minute earlier and it would have gone off in the storage case (ammo box) with all my other packs and likely would have burned my trailer and airplanes up with it. At best it would have coated all my hobby stuff with soot and smoke. A lipo that is more than a little puffed is dangerous. You should think about getting rid of it. It is not worth burning down your house or damaging a plane or the piece of equipment it is powering. Youtube has plenty of videos of LIPO fires and counting mine I have seen three in person and they are pretty wild.

Long story short, Joe you may be pushing your packs a little to far, but it does not sound like you are abusing them. Like anything if it is continually operated at its limits it will fail earlier. I imagine that your packs have quite a few cycles on them with the amount of work you have been doing. You may want to up your voltage cut off a little to help lengthen your pack life and always balance charge them.


Oh, and to the original question in the thread to test capacity (mah) you have to use the pack in its usual fashion and time the run time you are getting and see what the digital charger is putting back into it.